Its been a while since my airberlin trip, and I would like to write about it.
DO NOT EVER FLY WITH AIR BERLIN!!!
My route was LAX-DUS-MUC then VIE-DUS-LAX
LAX-DUS: The plane was meh, a A330-200 and I was sitting in the last row so I was sitting next the the crew rest area, which is relatively quiet. I would recommend rows 48-50 if you do not get sick sitting in the back of the plane. Food is also meh. IFE is actually better than what I expected, it is not the worst in the world, but nothing compared to Emirates. Just another economy class long haul airline, nothing special.
DUS-MUC: A320, I slept the whole flight, but the seats were standard, and at least they use jetbridge (Ryanair)
However, I was traveling with my instrument and I have a performance in a few days, BUT THEY LOST MY INSTRUMENT. I checked it, and I have never traveled with my instrument before, so I was expecting it to be on the luggage belt when I arrived in Munich. I had to get a rental instrument and it was a pain. I got my instrument back, but my performance was impacted.
VIE-DUS: Another A320, and I slept on the whole flight again, so nothing special.
DUS-LAX: A330-200, nothing special, same as the one I came from
My recommendation is: unless they have some dirt cheap fares, do not fly with them. Fly with Lufthansa, their service is better, their planes are better, and they lose less luggage compared to Air Berlin.